Does Weed Raise or Lower Blood Pressure? What Studies Show

Does weed raise or lower your blood pressure? Short answer: both, depending on timing. Cannabis can briefly raise blood pressure and heart rate right after use and may lower it a few hours later, but there's no good evidence it treats hypertension, and some studies link long-term use to cardiovascular risk. For many patients weighing cannabis as a treatment option, side effects like these are a constant worry.

In a country like the U.S., where high blood pressure is one of the most common health problems around, the question of whether marijuana raises or lowers blood pressure comes up a lot. But the answer isn't as simple as you might think.

What is blood pressure and how is it measured?

Blood pressure is the force your blood puts on the walls of your arteries as it moves through the cardiovascular system, carrying oxygen and energy around the body. It's measured with two numbers: systolic pressure, the pressure in your arteries when your heart beats, and diastolic pressure, the pressure between beats.

Normal blood pressure is below 120/80 mm Hg. As it climbs, it can reach elevated levels (120-129 systolic and under 80 diastolic), then stage 1 high blood pressure (130-139/80-89 mm Hg) and finally stage 2 (140/90 mm Hg or higher), also known as hypertension. Anything above 180/120 mm Hg needs immediate medical attention.

Marijuana and blood pressure: how does it affect hypertension?

Researchers are digging hard into how marijuana might affect blood pressure. But cannabis's effects here can vary a lot depending on several factors.

To get a better picture of how marijuana interacts with the body, you have to look at the endocannabinoid system (ECS). This system, made up of receptors, neurotransmitters and enzymes, plays a vital role in a wide range of physical and mental functions, including cardiovascular control.

In animal studies, hypertensive cats showed lower blood pressure after receiving THC. That doesn't mean people with chronic hypertension should turn to cannabis, though: the ways it's administered and the compounds involved can vary a lot.

Does weed raise or lower blood pressure? What other studies say

Some studies suggest that occasional marijuana use can temporarily raise blood pressure, but that response seems to fade in regular users.

Other researchers, though, have seen a moderate rise in systolic pressure after cannabis use, with no effect on diastolic pressure.

On the flip side, human studies have looked at whether marijuana might lower blood pressure in the short term, especially in older adults. Some results point to a drop in blood pressure after several hours, but more research is needed to fully understand these effects and what they mean.

To sum up: marijuana may have acute vasodilating effects (it widens blood vessels), which can lead to a temporary dip in blood pressure, but more research is needed to understand its impact on hypertension and whether it could ever be a viable treatment.

Marijuana and blood pressure: long-term effects

Long-term studies on cannabis and hypertension are scarce, and the ones that exist haven't managed to separate marijuana use from other factors that affect blood pressure. For example, regular cannabis users often smoke tobacco too, a habit well known for its harmful effects on blood pressure and heart health.

A multi-year study from Georgia State University with 1,213 participants found that people who used marijuana had a higher risk of dying from hypertension and heart disease than non-users. The researchers acknowledged, though, that it was hard to account for other factors in their results.

On top of that, the study counted anyone who admitted to smoking marijuana at least once as a "user," without separating occasional from regular users.

More studies on marijuana and blood pressure

A more recent 2019 study concluded that cannabis's effects on the cardiovascular system are cause for concern, identifying a number of negative impacts on the heart and blood vessels linked to marijuana use.

A 2002 paper highlights a possible gap between how marijuana affects blood pressure in animals and in humans. In some animals it seems to cause hypotension (a drop in blood pressure), but it's not clear those results carry over to people.

Current findings don't support using marijuana to treat hypertension, but it's worth noting that many studies haven't been able to properly isolate marijuana as the only cause of the effects they observed.

Plus, most studies look at marijuana as a whole, without separating out the effects of specific compounds like individual cannabinoids.

Does smoking weed lower blood pressure? Here's what we know

The relationship between marijuana and blood pressure still isn't fully clear. But based on what we know so far, people with hypertension should be careful with cannabis. There's evidence that it could make the problem worse rather than better, especially when it's smoked with tobacco.

That said, in some cases, like when high blood pressure is tied to lifestyle factors such as stress, cannabis might affect things differently. Keep in mind that everyone reacts to cannabis differently.

It's key to understand that even if marijuana helps bring blood pressure down, it would only be treating the symptom, not the underlying cause. If stress is the main driver of your hypertension, the real fix is tackling and reducing that stress, not leaning on cannabis alone. And if you're on blood pressure meds, talk to your doctor first.

CBD and blood pressure

CBD (cannabidiol) on its own is a different story. One study with nine male participants looked at whether a 600 mg dose of CBD could lower blood pressure.

The study is limited by its tiny sample, but it opens the door to more research on how CBD affects blood pressure, which could bring more encouraging results down the line.